Apparatus and method thereof

ABSTRACT

The invention discloses a apparatus and related method. The apparatus comprises a front-end circuit, a back-end circuit and a determining unit. The front-end circuit is for measuring an image signal, determining the mode of the image signal according to the data of the image signal, and fetching image signal of the image signal. The back-end circuit is for processing the image signal according to the above-mentioned mode, and generating a feedback signal according to the status of the image signal after fetching there-to-fore. The determining unit is for generating a control signal to the front-end circuit according to the feedback signal for adjusting the setting of the mode.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to display technology, particularly to a apparatusand a method thereof.

2. Description of the Related Art

At present, a digital display device, such as: liquid crystal display(LCD), plasma display panel (PDP), has gradually become the mainstreamproduct in the market. And, in general, each of the panel has a nativephysical resolution. Furthermore, the resolution of an image signaloutputted by a general video signal source, such as personal computer(PC), digital video disc/disk player (DVD Player), and so forth, may notbe exactly equal to the native resolution of the panel. In other words,if a receiving circuit is applied in a LCD panel having 1280×1024resolution, then the receiving circuit has to perform scaling upoperation on the 640×480, 800×600, or 1024×768 image signal to match thenative resolution of the panel of the digital display device.

BRIEF SUMMARY OF THE INVENTION

In light of the above mentioned problems, an object of the invention isto provide an apparatus and a method thereof. The detector and themethod thereof can automatically detect the resolution of an input imageand can adjust, such as scaling up or scaling down, the resolution ofthe input image when the resolution of the input image is not match tothe native resolution of the panel so that the adjusted input imageresolution is match to the native resolution of the flat panel displaydevice. Then, correctly displaying the image on the display device canbe achieved.

One embodiment of the invention provides an apparatus for mode detectionfor a display device. The apparatus comprises a front-end circuit, aback-end circuit and a determining unit. The front-end circuit is usedfor fetching an image signal according to a determined mode to generatea fetched image signal, and for adjusting the determined mode accordingto a control signal. The back-end circuit, coupled to the front-endcircuit, is used for processing the fetched image signal according tothe determined mode, and for generating an indication signal when theback-end Circuit Occurs all abnormal status. The determining unit,coupled to the front-end circuit and the back-end circuit, is used forgenerating the control signal according to the indication signalindicating the determined mode needs to adjust.

One embodiment of the invention provides a method for detection mode fora display device. The method comprises the following steps:

Receiving an image signal; selecting one of a plurality of modes togenerate a determined mode; fetching the image signal according to thedetermined mode to produce a fetched image signal; processing thefetched image signal according to the determined mode to produce aprocessed image signal; generating an indication signal according to astate of the step of processing; and adjusting the determined modeaccording to the indication signal indicating the determined mode needsto adjust.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram illustrating the apparatus according toone embodiment of the invention;

FIG. 2A shows a schematic diagram illustrating the relevant imageattribute parameters of the frame of a digital image data;

FIG. 2B shows a schematic diagram illustrating the frame of an analogimage data;

FIG. 3 shows a schematic diagram illustrating the verticalsynchronization signal and the outputting synchronization signalaccording to one embodiment of the invention; and

FIG. 4 shows a flow chart illustrating the method according to oneembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Generally, the image signals outputted from various video signal sourcesare generated according to a specific specification and each imageaccording to a specific specification has a specific resolution. And inorder to facilitate the receiving circuit of the display device to beable to detect the resolution of the image signal when inputting theimage signal, it is necessary to perform mode detection on the imagesignal.

The format of the image signal further comprises other control signalsbesides the image data. For example, a general video or image signalfurther comprises data, horizontal synchronization signal (HS), verticalsynchronization signal (VS), data enable signal (DEN), and so forth.Therefore, when performing the mode detection according to oneembodiment of the invention, a measuring method can be used to obtainthe relevant parameters of the image signal and thus which supportingmode (what kind of resolution) that the input image signal belongs tocan be known or determined. And, the measuring method can measure thefrequency, the period, the bandwidth, or the polarity of thesynchronization signal HS or VS; or the total clock (CK) counts used bythe overall synchronization signal.

It should be noted that, in the following discussion the embodiments ofthe invention is based on the flat panel display device, but with minormodifications, the technology of the invention is also applicable tovarious other display devices, such as curved surface display device,various possible forms of digital or analog display devices to bedeveloped in future, or can even be applied in the display devices withvariable physical resolution that may be developed in the future,without deviating from what is claimed for the invention.

FIG. 1 shows an apparatus 10 for mode detection for a display device andan interfacing circuit (IFC) that is coupled to the display deviceaccording to one embodiment of the invention. The apparatus 10 may beapplicable to a display device. The apparatus 10 is for detecting theresolution of an image signal (IS) outputted from the video signalsource. The image signal (IS) can be a digital signal or an analogsignal. As it is a digital signal, the image signal (IS) comprises ahorizontal synchronization signal (HS), a vertical synchronizationsignal (VS), a clock signal (CK), a data enable signal (DEN), and imagedata (DA). As it is an analog signal, the image signal (IS) includes ahorizontal synchronization signal (HS), a vertical synchronizationsignal (VS), a clock signal (CK), and image data (DA).

The apparatus 10 includes a front-end circuit 11, a back-end circuit 12,and a determining unit 13.

The front-end circuit 11 fetches the image signal (IS) according to adetermined mode to generate a fetched image signal (IS′), and adjuststhe determined mode according to a control signal DT. Further, thefront-end circuit 11 measures the image signal (IS) to produce at leastone parameter (IF), and selects one of a plurality of modes as thedetermined mode according to the at least one parameter (IF).Furthermore, the front-end circuit 11 can also reselect the proper modeor adjusts the vertical resolution or the horizontal resolution of thecurrent mode according to the control signal (DT).

In one embodiment of the invention, the front-end circuit 11 comprises ameasuring unit 111, a mode detecting unit 112, and a data fetching unit113. The measuring unit 111 measures the horizontal synchronizationsignal (HS) or the vertical synchronization signal (VS), or the (HS) andthe (VS) at the same time, to acquire the at least one parameter (IF).

The at least one parameter (IF) may comprise a start point of an activearea of the image signal (IS), at least one of period of thesynchronization signal, polarity of the synchronization signal, a framewidth (Htotal) of the image signal, a frame height (Vtotal) of the imagesignal, or at least one of frequency, period, bandwidth, polarity, framewidth, and a frame height, provided by the horizontal synchronizationsignal (HS) or the vertical synchronization signal (VS), or both of the(HS) and the (VS).

The mode detecting unit 112 selecting one of the plurality of the modesaccording to the at least one parameter (IF) generated by the measuringunit 111 to generate the determined mode. Thereafter, the mode detectingunit 112 generates a corresponding virtual (output) horizontalsynchronization signal (HSi) and a corresponding virtual (output)vertical synchronization signal (VSi) according to the determined mode.Then, the data fetching unit 113 fetches the image signal (IS) accordingto the virtual (output) horizontal synchronization signal (HSi) and thevirtual (output) vertical synchronization signal (VSi) to generate thefetched image signal (IS′).

The back-end circuit 12, coupled to the front-end circuit 11, processesthe fetched image signal (IS′) generated from the data fetching unit 113according to the determined mode, sets the fetched image signal (IS′) tobe properly scaled according to the current determined mode, and outputsa scaled and fetched image signal (IS″) to the flat panel display devicevia the interface circuit (IFC). On the other hand, the back-end circuit12 generates an indication signal (FB), when the back-end circuit 12occurs an abnormal status. According to one embodiment of the invention,the back-end circuit 12 includes a buffer 121 and a scalar 122. Thebuffer 121 may be a line buffer. Of course, in another embodiment of theinvention, the buffer 121 may be another current-existed orfuture-developed buffer. The buffer 121 temporarily stores the fetchedimage signal (IS′), which usually is the pixel data for performingscaling process, and the above-mentioned abnormal status comprises anunderflow or overflow state of the buffer 121. The scalar 122 is forscaling the fetched image signal (IS′) according to the scaling factor.The scaling factor is the ratio of the resolution determined in thedetermined mode to the native resolution of the panel of the displaydevice.

The determining unit 13, coupled to the front-end circuit and theback-end circuit, receives the indication signal (FB), and generates thecontrol signal (DT) to the front-end circuit 11 according to theindication signal (FB) indicating the determined mode needs to adjust(such as the result of determining if the scaled and fetched imagesignal (IS″) can be correctly displayed) to maintain the current mode orto select another suitable mode. According to one embodiment of theinvention, the control signal (DT) is inputted to the mode detectingunit 112 for assigning one of the pre-determined modes as the currentmode or for changing the setting of the vertical resolution of thecurrent mode.

Detail description of the operating method of the apparatus 10 accordingto one embodiment of the invention will be given in the followings. Itis assumed that the native resolution of a panel is 1280×1024. And it isassumed that the mode supported by the front-end circuit 11 comprises afirst mode (640×480), a second mode (800×600), a third mode (1024×768),a fourth mode (1280×1024), a fifth mode (1280×768), and a sixth mode(1366×768). It should be noted that the above-mentioned modes arecommonly used modes, but the invention is not limited to theabove-mentioned modes. The modes having other resolution levels can allbe utilized in other embodiments.

FIG. 2A shows the image attribute parameters relevant to a frame of adigital image data of the image signal (IS). The frame comprises anactive area (A) and a blank (or inactive) area (B). The parametersrelevant to a frame comprise a frame width (Htotal), a frame height(Vtotal), a horizontal start point (Hstart) of the active area, avertical start point (Vstart) of the active area, an active area width(Hwidth), and an active area height (Vhight). And the horizontalsynchronization signal (HS) comprises a front porch (FP), a horizontaldata enabling area (H_(DEN)), and a back porch (BP). The meaning foreach of the above-mentioned parameters can be understood by those whoare skilled in the art and will not be repeated hereinafter.

Please refer to FIGS. 1 and 2A. At first, the video signal sourceoutputs the image signal (IS) to the apparatus 10. Then, the measuringunit 111 of the apparatus 10 receives and measures the image signal(IS). For example, the measuring unit 111 measures the horizontalsynchronization signal (HS) or the vertical synchronization signal (VS)of the image signal (IS) to derive the at least one parameter (IF)(pixel values, frequency, period, bandwidth, or polarity, etc.). Then,the measuring circuit 111 compares the parameter (IF) with apre-determined value in a look-up-table (not shown in the figure) toderive a comparison result. For example, the measuring unit 11 maycompare pixel values of the image signal (IS) with a predetermined valueto determine a comparison result which is a start point of an activearea of the image signal (IS). After that, according to the comparisonresult, the mode detecting unit 112 determines if the build-in modes cansupport the image signal (IS). For examples, the mode detecting unit 112determines the image signal (IS) belongs to the second mode (800×600).Thus, the 800×600 resolution is utilized as the current determined mode.Therefore, according to the pre-determined horizontal and verticalresolution (800,600), the mode detecting unit 112 generates thecorresponding virtual (output) horizontal and vertical synchronizationsignals (HSi, VSi). The data fetching unit 113 then receives the imagesignal (IS) according to HSi and VSi to generate the fetched imagesignal (IS′).

According to one embodiment of the invention, the measuring unit 111 maymeasure at least one of period of the horizontal synchronization signal(HS) of the image signal (IS) only and determine the possible resolutionof the image signal (IS) according to the period data of the horizontalsynchronization signal (HS). Of course, by measuring more data (such as:the polarity of the horizontal synchronization signal (HS), the periodof the vertical synchronization signal (VS), the polarity of thevertical synchronization signal (VS), and so forth), the determinedresolution of the image signal (IS) can be more accurate. Once it isfound that the determined resolution is not correct, another possibleresolution can be set until the correct resolution is determined. Inthis embodiment of the invention, the measuring unit 111 may beimplemented by a counter. The counter counts the interval between twohorizontal synchronization signal (HS) pulses according to a clock (suchas: a free-running clock, a pixel clock of the image signal (IS), or anyclock selected from the internal clocks).

It should be noted that the apparatus 10 has already detected the modeof the image signal (IS) according to the descriptions up to now. Inanother embodiment of the invention, in order to receive the imagesignal (IS) more accurately to have the display device display the imagemore precisely, the front-end circuit 11 can perform the measurement andprocessing of the start point of the active area of the frame of theimage signal (IS), that is, the horizontal start point (Hstart) and thevertical start point (Vstart). For example, as the image signal (IS) isa digital signal, the measuring un it 111 determines a horizontal startpoint (Hstart) and/or a vertical start point (Vstart) of the active areaof the frame of the image signal (IS) according to the data enablesignal (H_(DEN)), so that the data fetching unit 113 may fetch the imagesignal (IS) according to the start point (Hstart and Vstart). As theimage signal (IS) is an analog signal, the measuring unit 111 compareseach pixel values of the image signal (IS) with a pre-determined valueto determine a start point of an active area of the image signal, thatis, a horizontal start point (Hstart) and a vertical start point(Vstart), and supplies to the data fetching unit 113 for fetching theimage signal (IS). For example, in the analog image signal (IS) as shownin FIG. 2B, the comparison between the pixel and the pre-determinedvalue can be determined by utilizing the pixel brightness value. It isassumed that the pixel brightness in the active area A is larger thanthe pre-determined value 16 and the pixel brightness in the blank area Bis less than the pre-determined value 16. During operation, themeasuring unit 111 scans each pixel of the frame of the image signal(IS), one by one from left to right and from top to down, and comparesthe brightness value of each pixel with the pre-determined value 16.Then, the position of the first pixel, having a brightness value largerthan 16 and being closest to the top of the frame while scanning, is thevertical start point (Vstart) of the active area. The position of thefirst pixel, having a brightness value larger than 16 and being closestto the left of the frame while scanning, is the horizontal start point(Hstart) of the active area. Thus, the start point of the active area(A) of the frame can be found by such a method.

Description of the operation of the back-end circuit 12 and thedetermining unit 13 according to one embodiment of the invention,possible special situations, and the corresponding handling methods willbe given in the followings.

At first, the buffer 121 receives and temporarily stores the fetchedimage signal (IS′). Since the native resolution of the panel is1280×1024, the scalar 122 sets the fetched image signal (IS′) accordingto the second mode (800×600) correspondingly by scaling up the fetchedimage signal (IS′) properly to match the 1280×1024 resolution of thepanel, and outputs the scaled and fetched image signal (IS″) to thepanel via the interface circuit (IFC) for displaying the image. Itshould be noted that, if the status of the above-mentioned fetched imagesignal (IS′) is abnormal, such as: the resolution of the image signal(IS) determined by the system is 800×600 but the resolution of the imagesignal (IS) inputted is actually 640×480, the back-end circuit 12 willdetect that the active area (A′) of the determined 800×600 resolutionsurpasses the next vertical synchronization signal (VS) during theprocessing process, as shown in FIG. 3. In one embodiment of theinvention, the data fetching unit 113 will stop fetching data whendetecting the pulse of the next vertical synchronization signal (VS).Thereby, the buffer 121 does not contain sufficient image data andunderflow phenomenon (A) will happen. Such an erroneous displayingphenomenon is an underflow phenomenon that happens when the determinedvertical resolution is larger than the actual vertical resolution of theimage signal.

At the same time, the back-end circuit 12 generates the indicationsignal (FB) to the determining unit 13 according to the above-mentionedunderflow status. Then, the determining unit 13 generates a controlsignal (DT) to the measuring unit 111 according to the data provided inindication signal (FB) to have the mode detecting unit 112 adjust thecurrent determined mode to the first mode (640×480) so that the datafetching unit 113 can correctly fetch the image signal (IS). In anotherembodiment of the invention, an approximate mode can be selected or thevertical resolution of the mode is modified directly for usage. Or,after learning the vertical resolution of the approximate mode (forexample, if the line count of the vertical resolution is already knownto be approximately 700 lines during the measuring process, the1280×1024, 1366×768, 1280×768, 1024×768, and so forth, resolutions areincorrect, that is, those modes having the vertical resolution largerthan 700 are incorrect), the incorrect modes can be excluded directlyand the closer second mode (800×600) is searched directly so that theprocessing can be speeded up. If the underflow phenomenon still happensunder the second mode (800×600), then it is learned that the 800×600resolution is still incorrect and the next mode will be searched (thatis, the first mode (640×480)) until the correct resolution is found.

Furthermore, if horizontal conflict happens in the apparatus 10 whendetermining the image signal resolution (for example, it is found thatthe vertical resolutions is 768 for either the 1280×768 or 1366×768 andit is unable to determine to use either the 1280×768 or 1366×768), thenthe measuring unit 111 can be utilized to directly measure the clock(CK) Count required by the data enable area of the horizontalsynchronization signal (HS). If the clock count is 1280, the 1280×768mode is selected and vice versa.

FIG. 4 shows the flow chart of a method for detection mode for a displayaccording to one embodiment of the invention. The method, applicable toa display device, comprises the following steps:

Step S402: start;

Step S404: receiving an image signal comprising an input horizontalsynchronization signal and an input vertical synchronization signal;

Step S406: selecting one of a plurality of predetermined modes accordingto the at least one parameter to generate a selected (determined) mode,where the pre-determined modes may be predetermined or provided by alook-up-table or a hardware circuit or software according to the relatedinformation of the image signal;

Step S408: processing the image signal according to the selected mode;and

Step S410: generating a control signal to adjust the selected mode whenthe step of processing occurs an abnormal state, wherein the abnormalstate may comprise an overflow or underflow phenomenon.

Please note that the image signal may further comprise a data enablesignal and the method may further comprise the step of determining ahorizontal start point (H-start) and a vertical start point (V-start) ofthe active area of a frame of the image data according to the dataenable signal, wherein the at least one parameter comprises thehorizontal start point (H-start) and the vertical start point (V-start).In one embodiment, the method may further comprise the step ofdetermining a horizontal start point (H-start) and a vertical startpoint (V-start) of the active area of a frame of the image data. Inanother embodiment, the Step S408 may comprise the steps of temporarilystoring image data of the image signal, and scaling the image data togenerate a scaled image data according to the selected mode. In anotherembodiment, the method may further comprise a step of fetching the imagesignal according to the determined mode to produce a fetched imagesignal to be processed by the step 408. In another embodiment, themethod may further comprise a step of generating an indication signalaccording to a state of the step of processing by the step 408. Inanother embodiment, the step S406 further comprises the step ofmeasuring the image signal to produce at least one parameter; comparingthe at least one parameter with a predetermined value; and selecting oneof the plurality of the modes according to the comparison result.

In conclusion, the mode detector and the method thereof according to theinvention are able to detect the resolution of the image signalautomatically when inputting the image signal. Furthermore, because theembodiments of the invention use the back-end circuit to processfeedback control, the apparatus and the method thereof can correctlydetermine the mode of the image signal (IS) without referencing therelated information of the image signal (IS).

Although the description of the invention is by way of above-mentionedexamples of embodiment, however, it should not be construed as anylimitation on the scope of the invention. Various modifications orchanges can be performed by those who are skilled in the art withoutdeviating from the scope of the invention.

1. An apparatus for mode detection for a display device, comprising: afront-end circuit, for fetching an image signal according to adetermined mode to generate a fetched image signal, and adjusting thedetermined mode according to a control signal; a back-end circuit,coupled to the front-end circuit, for processing the fetched imagesignal according to the determined mode, and for generating anindication signal when the back-end circuit occurs an abnormal status;and a determining unit, coupled to the front-end circuit and theback-end circuit, for generating the control signal according to theindication signal indicating the determined mode needs to adjust.
 2. Theapparatus according to claim 1, wherein the front-end circuit measuresthe image signal to produce at least one parameter, and selects one of aplurality of modes as the determined mode according to the at least oneparameter.
 3. The apparatus according to claim 1, wherein the front-endcircuit comprises: a measuring unit, for measuring a synchronizationsignal of the image signal to acquire the at least one parameter; a modedetecting unit, for selecting one of the plurality of the modesaccording to the at least one parameter to generate the determined modeand for generating a corresponding output horizontal synchronizationsignal and a corresponding output vertical synchronization signalaccording to the determined mode; and a data fetching unit, for fetchingthe image signal according to the output horizontal synchronizationsignal and the output vertical synchronization signal to generate thefetched image signal.
 4. The apparatus according to claim 3, wherein themeasuring unit determines a start point of an active area of the imagesignal, the at least one parameter comprises the start point, and thedata fetching unit fetches the image signal according to a start point.5. The apparatus according to claim 3, wherein the measuring unitcompares pixel values of the image signal with a predetermined value todetermine a start point of an active area of the image signal.
 6. Theapparatus according to claim 3, wherein the image signal comprises adata enable signal; and the measuring unit determines a start point ofan active area of the image signal according to the data enable signal.7. The apparatus according to claim 6, wherein the start point comprisesa horizontal start point (H-start) and a vertical start point (V-start).8. The apparatus according to claim 2, wherein the at least oneparameter comprises at least one of period of the synchronizationsignal, frame width of the image signal, a frame height of the imagesignal, and a start point of the active area of the image signal.
 9. Theapparatus according to claim 1, wherein back-end circuit comprises abuffer for temporarily storing the fetched image signal, and theabnormal status comprises an underflow or overflow state of the buffer.10. The apparatus according to claim 1, wherein the back-end circuitcomprises: a buffer for temporarily storing the fetched image signal;and a scalar for scaling the fetched image signal according to thedetermined mode.
 11. The apparatus according to claim 10, wherein thefront-end circuit adjusts the determined mode according the controlsignal to prevent an underflow or overflow state of the buffer.
 12. Amethod for detection mode for a display device, comprising: receiving animage signal; selecting one of a plurality of modes to generate adetermined mode; fetching the image signal according to the determinedmode to produce a fetched image signal; processing the fetched imagesignal according to the determined mode to produce a processed imagesignal; generating an indication signal according to a state of the stepof processing; and adjusting the determined mode according to theindication signal indicating the determined mode needs to adjust. 13.The method according to claim 12, wherein the step of processingcomprises: temporarily storing the fetched image signal in a buffer; andscaling the fetched image signal to produce the processed image signal.14. The method according to claim 13, wherein the indication signal isgenerated when the buffer occurs an overflow or underflow state.
 15. Themethod according to claim 12, wherein the step of selecting comprises:measuring the image signal to produce at least one parameter; comparingthe at least one parameter with a predetermined value; and selecting oneof the plurality of the modes according to the comparison result. 16.The method according to claim 15, wherein the at least one parametercomprises at least one of period of the synchronization signal, framewidth of the image signal, a frame height of the image signal, and astart point of the active area of the image signal.
 17. A method fordetection mode for a display device, comprising: receiving an imagesignal; selecting one of a plurality of modes to generate a determinedmode; fetching the image signal according to the determined mode toproduce a fetched image signal; temporarily storing the fetched imagesignal in a buffer; processing the fetched image signal according to thedetermined mode; and adjusting the determined mode when the bufferoccurs an overflow or underflow state.
 18. The method according to claim17, wherein the step of selecting comprises: measuring the image signalto produce at least one parameter; comparing the at least one parameterwith a predetermined value; and selecting one of the plurality of themodes according to the comparison result.
 19. The method according toclaim 18, wherein the at least one parameter comprises at least one ofperiod of the synchronization signal, frame width of the image signal, aframe height of the image signal, and a start point of the active areaof the image signal.